1. Field of the Invention
The present invention relates to a method for detecting lane departure and an apparatus thereof, in that the images are used for the recognition of lane lines, and a quadratic curve fitting equation is used to derive a displacement of lane departure of a vehicle and a lane curvature so as to determine whether the vehicle travels along the normal path and thus a warning is issued.
2. Description of Related Art
Nowadays, with the popularity of vehicles, the geographic distance of the world is substantially shortened. However, such transportation improvement apparently accompanies the increment of traffic accidents. Therefore, more and more automotive companies worldwide have been endeavoring to develop advanced safety technologies, which can assist the driver in safer operation of the vehicle and then reduce the possibility of traffic accident occurrence.
Most of traffic accidents are induced from human driving errors, such as fatigue or inattention. Although there are some recent researches being carried out to directly detect the driver's drowsiness via eye blinking or brain waves, the related apparatuses in reality are not easy to be popularized due to the recognition accuracy and the cost. In the prior arts, the front-end sensing units used for vehicle protection and warning technologies are mainly concentrated in the use of ultrasonic waves, radars or light reflection sensors. For instance, each side of a vehicle is equipped with an alarm apparatus, which consists of a voltage power supply, a light sensor, a signal amplifier, a voltage comparison amplifier and an alarm display. Based on the difference of reflected light intensity between the road surfaces with and without the line marking, an electric current would be generated. Then this current would be modulated to an appropriate voltage by the signal amplifier and outputted to the alarm display to warn the driver of the danger of departure from the lane.
Recently, with enhancement of image processing technology, CCD/CMOS cameras gradually become standard equipment on new-generation vehicles for various safety applications, such as parking assist, lane, vehicle and pedestrian detections. For example, a conventional lane departure warning apparatus and method includes a lane image capturing unit, a vehicle drift detection unit, and an alarm unit for lane departure prevention. The method for determining the drift of a vehicle from the lane includes the steps of image input, image analyzing and processing, region of interest (ROI) setting, lane drift detection, and alarm issuing to alert the driver to the danger of unintentional departure and then enhance the driving safety. Moreover, for the alarm issuing, the patent further includes an auto-judgment process to decide whether it is necessary to disable the alarm unit temporarily for avoiding overly interfering with the driver due to the frequent warnings.
However, due to the prior art is only based on the comparison of the lane line markings and the traveling track of a vehicle for assuring whether the vehicle drifts away from the normal path, the track estimation process is ignored. Thus the prior art will result in fault alarms or the error timing of alarm issuing. Therefore, there is an eager demand for a novel design that can provide the method and apparatus for improving the shortcomings in the prior arts.